1. Field of the Invention
The invention pertains to the field of X-ray lenses. More particularly, the invention pertains to a method of manufacturing transmission type X-ray lenses, particularly a method of manufacturing short focus lenses.
2. Description of Related Art
While it is well known that the reflectance of X-rays compared to their transmission is very small, prior art X-ray lenses, used reflecting type which used Bragg reflection from many layers despite the low intensity of the focused X-ray.
This is due to the fact that n=1xe2x88x92xcex4(xcex4 less than 0.001), if n is the refraction factor of X-rays. That is to say, because it is only slightly less than 1, X-rays for the most part do not refract. Because of that it has been extremely difficult to manufacture X-ray transmission lenses at a practical level with the same method as when dealing with visible light.
A transmission type lens different from that for visible light was disclosed as a transmission type lens for use with X-rays in Japanese Patent 2526409 (U.S. Pat. No. 5,594,773). A summary of that invention is shown in FIG. 3. This invention has numerous cylindrically shaped boring holes 32 cut in a lens material component 31 and these boring holes 32 are lined up following a specified axis. Then, when this X-ray lens is used, the X-ray incidence direction 33 is the direction that boring holes 32 are lined up.
As previously noted, in a transmission type X-ray lens which converges X-rays at a short focal length, in order to converge incident X-rays of an order of a nanometer or less at a practical focal length, the required diameter of cylindrically shaped boring holes 32 is an order of several nm and processing of their curved surfaces is extremely difficult. In addition, lining up the numerous cylindrically shaped bored holes 32 forming a parallel line following the specified axis which becomes the X-ray incidence angle 33 must be done very precisely. The inventor has formed boring holes like these in a diamond with machine processing and tried manufacturing this transmission type X-ray lens but there were extreme technical problems and this had to be abandoned.
In addition, it was acknowledged that the material qualities of metal would significantly change in an order of several nm, as seen, for example, in the phenomenon of the melting point of gold significantly lowering.
The present invention, in proposing to shorten the focal length in X-ray lenses, departs from idea of cutting cylindrically shaped holes in lens materials and takes as its purpose to provide a method of manufacturing transmission type X-ray lenses which does not require highly complex precision processing and will provide transmission type X-ray lenses with comparatively short focal lengths easily.
The present invention, in order to solve the previously noted problems, provides a method of manufacturing X-ray lenses which transmit X-rays comprising a first step of providing a layer of liquid on the flat surface of a first substrate, a second step of arranging numerous pipe-shaped lens components in a row following an axis which extends parallel to the flat surface in the layer of liquid, and a third step of holding the pipe-shaped lens components between the surface of a second substrate having a flat surface and the flat surface of the first substrate, and filling the liquid in spaces formed by the exterior surface of the pipe-shaped lens components and the flat surface of the first substrate or the flat surface of the second substrate.
By adopting the previously noted method, pipe-shaped lens components can be precisely lined up easily following a specified axis without requiring high technical precision seen from the aspect of commercial production and without being affected by the size of the pipe-shaped lens components.
In one embodiment of the invention, the second step arranges carbon nanotubes as the pipe-shaped lens components. The carbon nanotube referred to here is a nanometer (10xe2x88x929 m) order tube formed by three arms of carbon atoms tied together. What should be noted about the structure of this carbon nanotube is that it has a nanoscale thickness, it is pipe-shaped and that generally a six membered ring is arranged in a helical shape.
In the past carbon nanotubes have been noted for their conductivity and their utilization in computer wiring and electronic devices. By using these carbon nanotubes as structural material for X-ray lenses a method of manufacturing X-ray lenses that can refract incident X-rays of a nanometer order or less at levels where short focusing is possible can be offered.
Another embodiment of the invention includes a liquid which holds the pipe-shaped lens components and a pair of substrates which holds the liquid and numerous the pipe-shaped lens components, whereby surfaces facing the pipe-shaped lens components of the pair of substrates are both flat and the pipe-shaped lens components are lined up following the same direction.
By adopting this configuration a transmitted X-ray is gradually refracted and can be made to converge because numerous pipe-shaped lens components artificially configure numerous concave lenses. These pipe-shaped lens components can be carbon nanotubes. By using these carbon nanotubes, X-ray lenses that can refract incident X-rays of a nanometer order or less at levels where short focusing is possible can be offered.